Flotation method



Nov. 8, 1932.

J. P. RUTHfJR 1,886,979

FLOTATION METHOD Filed Jan. 2e. 1931 4f ff, 4, /f /f y 1: f i 9 fa f7 f40 0 77 I Y l C -"1 y "n l k/ gmc/vwo@ l A /Me 2 umy.

@ttor/mag Patented Nov. 8, 1932 UNITED STATES PATENT OFFICE i .Tosnirrr. RUTH, m., or nENvEn, i y

mach appnann mea :anaal-y 26,1931. serial ,110. 511,448.

This invention relates to improvements in methods for operating"flotation machines of the type (employed in separating mineral valuesfrom angue.

In themimng of metals it is now common practice to employ flotationmachines for the selective separation of the minerals from the gangue.It has been found from extensive experiments that flotation machinesoperate at their highest eiiciency only when they operate at `maximumcapacity and' with the present forms of flotation machines this is acondition that prevails only in mines where the ore supply is equal toor greater than the capacityof the machines employed.

A flotation machine is composed of a plu- .rality of units or cells,each'having a receiving conduit and a frothing chamber, an impe lerisilocated in a passageway that connects the receiving conduit and thefrothing chamber and this transfers the pulp from the former to thelatter and mixes it with air.

The froth overflows into a froth launder and the tailings from eachcell, except the last, is delivered to the receiving conduit of the nextcell in the series and the tailings from the last cell is conducted toa' vtailings dump. The

ulp is fed into .the receiving conduit of the Erst cell orunit in theseries and therefore passes succeively through the several cells ofwhich the machine is composed. Since some of the values are removed ineach cell,

it is evident that the richness 4of the pulp decreases as the pulpprogresses through the In designing flotation machines for mines, it iscustomary toprovide for sutlicient capacity to take care of the naximumoutput of the mine and as `a result the machines frequently operate on asuppl that is considerably below the capacity or which the machine-wasdesigned and therefore the eiliciency at which the machine operatesis below maximum which means that there is a loss Vof mineral valu thatcould have been `saved if the supply of pulp supplied were I have foundthat if a portion of the tailings, ,of being transferred to .the dump,is returned to the receiving conduit of the first cell of the machine,it is possible to operate the machine at maximum capacity at all times,regardless ofthe fact that the supply of pulp is less than the ca acityof the machine. It is obvious that i the maA` chine was operatin at fullcapacity in the ordinary way and the supply of pulp cut off and all ofthe tailings returned to the intake conduit of the first cell thequantity of ulp circulatingthrough he machine would) remain the sameexce ltfor the loss due to the froth overflow. If esh pulp to the extentof one-half of the capacity is supplied to the intake conduit of thefirstcell and one-half of the tailings returned, the machine will beoperating at maximum capacity and consequently at maximumeiliciency.

In order to more clearly define the method described above an apparatusby which it can be carried out will now be described land for thispurpose reference will be had to the ae. companying drawing in which:

Fig. 1 is a top-plan view of an assemblyof cells showinr the launder bymeans of which a portion of the tailings are returned tothe receivingconduit of the first cell;

Fig. 2 is aside elevation of the cell assembly and Fig. 3 is atransverse section through one of the cells.

The assembly illustrated comprises six cells 4 arranged one above theother as shown in Fig. 2, each of the cells has a receiving conduit 5and a frothing chamber 6. Line 7 in Fig. 3 indicates the ulp level andthe pulp overflow is indicate by reference number 8 while the frothoverflow is designated by numeral 9. A spout 10 is located underneatheach pulp overflow and is inclined so as to carry the pulp to thereceiving conduit of the next higher cell. A froth launder 11 extendsunderneath all of the froth overflows. The spout 10 from the last cellin the serie-s is connected with a launder 13 that extends to thereceiving conduit of the lowermost cell in the series. In order to varythe proportion of the total of the tailings that are returned, a plate14 is secured the inside of the spout 10 by a hinge, the 'nge is locatedat the lower edge of the plate 14 and its position is controlled by ascrew 15. If plate 14 is moved so as to c'ontact with both/sides ofspout 10, all of the tailings will be returned, if it is moved upagainst the side to 5 which it is hinged, none of the tailings will bereturned andany proportions between these extremes can be returned bymoving plate 14 to the corresponding intermediate position. c

1 The cells are each provided with animpeller 16 that is secured to thelower end of the impeller shaft 17.

The apparatus described is merely illustray tive and applicant doesnotwant'the same to beconsidered as in any way limiting the scope of hisclaims.

From the above it is evident that by returning a suflicient amount oftailin s and mixing them with the original pulp, t e ma- 20 chine canalways be operated at maximum capacity and eiiciency. It is also evidentthat by returning a portion of the tailings and having them pass throughthe machine, they will be subjected to a second operation that willremove an mineral values that would otherwise have en lost.

I consider that the discovery that flotation machines operate atgreatest efliciency when operating at` ull load capacity and that thiscondition can always be obtained regardless of the actual amount of pulpavailable by the simple expedient of returning a portion of the tailingsto the intake conduit of the first cell constitutes my invention and itis of great practical importance in this art.

Having described the invention what is Y claimed as new is: l

1. The method of operating a series connected group of flotationmachines so as to obtain the maximum efficiency when the pulp availableis less than that required for the capacity corresponding to maximumeiiciency which consists in returning tailings from the last cell of theseriesto the intake conduit '35 of the first cell in such amount thatthe returned tailings and the original pulp supply v will equal theamount necessary for 'maximum eiiciency.

2. The inethod of operating a flotation machine, having an intakeconduit and a tailings discharge, at maximum eliiciency when the pulpavailable is less than that which is required for maximum eiiciencywhich consists in returning so much of the tailings. to 55 the intakeconduit that the returned tailings and the supply of untreated pulptogether produce a load that corresponds to that which is required formaximum efliciency.

In testimony whereof I aix m si ature.

JOSEPH P. R T JB.

DISCLAIMER .-,Jeseph P. Ruth, Jr., Denver, Colo. FLo'rlurIorv MTHOD.

November 8, 1932. Disclaimer filed August 23, 15935, by the patentee.

Patent to the method therein defined only when made effective throughcertain specifically characterized apparatus of that vtypeillustrated insaid Letters- Patent, t0 Wit: i A

Flotation machines wherein the tailings stantial distanceabove the pulpfeed inlet to said cell unit the froth discharge from Saidv cell unit,and operative capacity sucient tomaintain thelv stantially empty. v

[O cial Gazette September 17, 1935.]-

discharge from each-cell unit is a'subandseparate from and belowfeedcompartment of itscell unit sub- Patent dated Hereby enters thisdisclaimer tovlimt the Iscope of claims Land 2 of said Letters whereinthe impeller element has an

